Solitary and Multiple Meningiomas: an Immunohistochemical Comparison

Introduction. Meningiomas are common primary tumors of brain meninges. These neoplasms develop from arachnoid cap cells and are multiple in 1 - 10% cases. Occasionally, significantly higher multiplicity rates have been reported, at least partially due to the increased application of computed tomography and magnetic resonance imaging in the diagnostics of intracranial pathologies. Meningiomas generally express progesterone receptors, but only few studies have focused on sex hormone receptor differences between solitary and multiple meningiomas. Similarly, there is limited information on cell proliferation and adhesion factors in solitary and multiple meningiomas.

Aim of the study. Was to evaluate the immunohistochemical differences in sex hormone receptor expression, cell proliferation and adhesion within solitary and multiple meningiomas.

Material and methods. In a retrospective study, 11 consecutive multiple meningiomas and 20 grade-matched solitary meningiomas were assessed by immunohistochemistry (IHC) to detect estrogen receptors (ER), progesterone receptors (PR), Ki-67 and neural cell adhesion molecule (NCAM). IHC was followed by quantitative microscopic evaluation. Descriptive and inferential statistics was applied including confidence interval (CI) analysis, Mann-Whitney U test and Spearmen correlation by IBM SPSS Statistics 22.0 software; p values less than 0.05 were regarded as statistically significant.

Results. Although PR were found in all samples, the mean expression was significantly lower in multiple meningiomas (p = 0.03): 30.0% (95% CI: 10.4 - 49.8) versus 70.6% (95% CI: 56.6 - 84.7) in solitary meningiomas. ER were invariably absent in both groups. The proliferation index did not differ in solitary and multiple tumors. There was a trend (p = 0.07) to higher mean expression of NCAM in multiple meningiomas than in control group: 48.3% (95% CI: 25.8 - 70.8) versus 24.6% (95% CI: 13.2 - 36.0), respectively. The multiple meningiomas showed diverse histological types and immunophenotypes in up to 33.3% patients.

Conclusions. Multiple meningiomas are characterized by significant down-regulation of PR and up-regulation of NCAM. The last finding can indicate neural differentiation and/ or peculiarities of cell adhesion and signaling that facilitate multifocal proliferation. Diverse histological types as well as PR and NCAM expression in separate meningiomas within same patient indicate independent multicentric origin.